i would be really grateful for some advice. i have been using an old fashioned pair of binos for a year or so but after getting more and more passionate about birding i decided to get some stronger strength binos. i recently purchased some opticron verano 10x42. they seemed perfect in the shop but the two times i have used them out in the field i have ended up with headaches. this may be coincidence but it may also be something to do with eye strain. i'd really like some advice so that i can exchange them if need be. i am aware that all binos are personal to the user and so after making a big purchase i want to be SURE these are the right ones for me.
thanks in advance!
Hi Eleanor, welcome to BirdForum, from all of us here on staff.
I've taken the liberty of moving your query to a Thread of it's own in a Forum that should get you more attention 
It sounds to me that the collimation may be out on your bino, you'll need to get it checked for alignment or return them, I think.
We have some very experienced people here on BF, I expect one (or more) of them will stop by here and give you more specific advice soon
Cheers,
Andy.
[QUOTE=eleanor]i would be really grateful for some advice. i have been using an old fashioned pair of binos for a year or so but after getting more and more passionate about birding i decided to get some stronger strength binos. i recently purchased some opticron verano 10x42. they seemed perfect in the shop but the two times i have used them out in the field i have ended up with headaches. this may be coincidence but it may also be something to do with eye strain. i'd really like some advice so that i can exchange them if need be. i am aware that all binos are personal to the user and so after making a big purchase i want to be SURE these are the right ones for me.
thanks in advance![/QUOTE]
Eleanor,
Nothing is worse than a headache in the field!
Carefully adjust the width of the binocular to your eyes. Then rest it on a desk, table, etc. so you can comfortably look through the binocular at a distant object without having to hold it. Don't lean forward and try to be as relaxed as possible. The goal is to eliminate normal physical strain (arms, neck, etc.) from the equation.
Look through the binocular and don't stop until one of two things happens:
1. Your eyes start to suffer and your head aches.
2. You're absolutely convinced you could repeatedly look through the binocular, without pause, for 5-10 minutes at a time. Sound strange? That's exactly what birders do at hawk counts.
If number 1 occurs the binocular is not optically aligned and you should return it. A good binocular can be used all day, often for several minutes at a time, with no eyestrain whatsoever.
Number 2 means the binocular is probably in good condition and your headaches are caused by muscle strain, bright light or a combination of variables. You might be able to adapt, but you might also prefer another model. 10X magnification can be hard for some people to handle and, if it is for you, the discomfort can generate physical stress, including headaches.
Good luck,
John